Marking apparatus with multiple marking modes

Abstract

Marking apparatus and method is described wherein an array of marker pins are carried by translational assembly which, in turn, is driven from stepper motors which perform in conjunction with high helix lead angle lead screws. Solenoid actuated pneumatic valves are employed to actuate the marker pins within an array thereof and the entire assemblage of motors, valves, translational mechanism, and control features are retained within a compact housing structure. The control system and associated translational mechanism is capable of driving the marker head assembly in matrix, raster, and continuous modes of operation. Speed of marking is enhanced through the employment of a masking procedure wherein the translational mechanism drives the marker head assembly only to locations where active character forming pixels are present.

We claim: 
     
       1. Apparatus for marking objects at a surface thereof with a sequence of characters formed by indentation, in response to data inputs, comprising: a housing having forward and rearward portions;   a translation mechanism mounted at said forward housing portion, including a carrier assembly slidably movable only in a transverse direction in response to a transverse drive input, a transverse screw assembly fixedly mounted upon and supported for rotation by said housing forward portion and rotatable in response to a rotational transverse drive input to provide said carrier assembly transverse drive input, a coupler component mounted to and supported by said housing forward portion for slidable movement only in a vertical direction in response to a vertical drive input, a vertical screw assembly fixedly mounted upon and supported for rotation by said housing forward portion and rotatable in response to a rotational vertical drive input to provide said coupler component vertical drive input, and a carriage component connected with said coupler component for driven movement in said vertical direction while being slidably movable thereon in said transverse direction and connected with said carrier assembly for movement in said transverse direction while being slidably movable thereon in said vertical direction;   a marker head assembly connectable with said carriage component, having a confronting portion positionable in spaced adjacency with said surface and including at least two marker pins, each having an impacting tip drivably movable into said surface in response to pneumatic control inputs;   a first motor mounted within and fixed to said housing rearward portion and responsive to a first control input to provide a transverse drive output of rotational extent corresponding with said first control input;   a first transmission assembly connected in driven relationship with said transverse drive output to derive said rotational transverse drive input for effecting the transverse directional movement of said carriage component;   a second motor mounted within and fixed to said housing rearward portion and responsive to a second control input to provide a vertical drive output of rotational extent corresponding with said second control input;   second transmission assembly connected in driven relationship with said vertical drive output to derive said rotational vertical drive input for effecting the vertical directional movement of said carriage component; and   control means responsive to said data inputs for deriving said first control input, said second control input and for effecting generation of said pneumatic control inputs to effect derivation of said characters at said surface.   
     
     
       2. The apparatus of claim 1 in which said marker head assembly includes: electrically actuated valve means mounted within said housing rearward portion forwardly of said first and second motors, having an input connectable with a source of gas under pressure, having valve output ports and actuable in response to said pneumatic control inputs to convey said gas from select said valve output ports; and   flexible conduit means coupled in gas transfer relationship between said valve output ports and a unique one of each said marker pins for effecting said movement of said impacting tip thereof.   
     
     
       3. The apparatus of claim 2 in which: said translation mechanism carriage component is configured as a manifold having chambers extending from pneumatic impact ports at a first surface thereof to pneumatic output ports at a second surface;   said flexible conduit means is coupled with said pneumatic output ports; and   said marker head assembly is connectable with said carriage component surface to effect said gas transfer relationship through said pneumatic output ports.   
     
     
       4. The apparatus of claim 1 in which: said transverse screw assembly includes a transverse screw shaft fixedly mounted upon said housing and drivably rotatable in response to said rotational transverse drive input and a transverse drive nut mounted in driven relationship thereon and connected in drive relationship with said carrier component, said transverse screw assembly effecting said transverse direction of movement of said carrier component in response to rotation of said transverse screw shaft.   
     
     
       5. The apparatus of claim 4 in which said transverse screw shaft is a high helix angle lead screw having a pitch selected to drivably move said transverse drive nut about one-half inch of travel per shaft revolution. 
     
     
       6. The apparatus of claim 4 in which said first transmission assembly comprises: a first transverse pulley coupled in drive relationship with said transverse screw shaft;   a second transverse pulley coupled in driven relationship with said first motor transverse drive output; and   a transverse drive belt mounted in driven relationship upon said second transverse pulley and in drive relationship with said transverse first pulley.   
     
     
       7. The apparatus of claim 1 in which: said vertical screw assembly includes a vertical screw shaft fixedly mounted upon said housing and drivably rotatable in response to said rotational vertical drive input and a vertical drive nut mounted in driven relationship thereon and connected in drive relationship with said coupler component, said vertical screw assembly effecting said vertical direction of movement of said coupler component in response to rotation of said vertical screw shaft.   
     
     
       8. The apparatus of claim 7 in which said vertical screw shaft is a high helix angle lead screw having a pitch selected to drivably move said vertical drive nut about one-half inch of travel per shaft revolution. 
     
     
       9. The apparatus of claim 7 in which said second transmission assembly comprises: a first vertical pulley coupled in drive relationship with said vertical screw shaft;   a second vertical pulley coupled in driven relationship with said second motor vertical drive output; and   a vertical drive belt mounted in driven relationship upon said second vertical pulley and in drive relationship with said first vertical pulley.   
     
     
       10. The apparatus of claim 1 in which said first and second motors are stepper motors. 
     
     
       11. Apparatus for marking a surface in response to data inputs with a sequence of mutually adjacent pixel characters formed within a matrix of rows and columns of dimension selected by a user, said columns being mutually spaced to define an initial, selected transverse pixel-to-pixel spacing, said apparatus comprising: a housing;   a translation mechanism mounted upon said housing having a positioning component movable in vertical and transverse directions in response to a drive input;   a marker head assembly connectable with said positioning component, having a confronting portion positionable in adjacency with said surface and including first and second marker pins having a predetermined pin-to-pin spacing, each having an impacting tip drivably movable into said surface in response to a pin drive input;   a translation drive assembly responsive to position signals for moving said positioning component to successive positions orienting said first and second marker pins at locations corresponding with a said pixel;   marker pin drive means responsive to pin actuation signals for providing said pin drive input; and   control means responsive to the value of said initial, user selected pixel-to-pixel spacing and the value of said pin-to-pin spacing to adjust said initial pixel-to-pixel spacing to derive an adjusted pixel-to-pixel spacing, said adjustment being an amount sufficient to constitute the quotient of said value of said pin-to-pin spacing divided by said adjusted pixel-to-pixel spacing to be substantially an integer, for deriving said pin actuation signals and said position signals to effect the formation of said characters exhibiting said adjusted said pixel-to-pixel spacing.   
     
     
       12. The apparatus of claim 11 in which said control means is responsive to successively add a predetermined spacing increment to said initial, user selected pixel-to-pixel spacing until said integer is present within a predetermined tolerance. 
     
     
       13. The apparatus of claim 12 in which said spacing increment is about 0.00001 inch. 
     
     
       14. The apparatus of claim 12 in which said tolerance is less than about 0.05. 
     
     
       15. The apparatus of claim 12 in which said tolerance is about 0.01. 
     
     
       16. The apparatus of claim 11 in which: said translation drive assembly comprises:   a first stepper motor mounted upon said housing and responsive to said position signals to provide a transverse drive output;   a first transmission assembly connected in driven relationship with said transverse drive output and in rotational drive relationship with said translation mechanism drive input for effecting the transverse directional movement of said positioning component;   a second stepper motor mounted upon said housing and responsive to said position signals to provide a vertical drive output; and   a second transmission assembly connected in driven relationship with said vertical drive output and in rotational drive relationship with said translation mechanism drive input for effecting the vertical directional movement of said positioning component.   
     
     
       17. The method for marking a surface in response to data inputs with a string of pixel-based characters, each being formed within a matrix of rows and columns representing available pixel locations, comprising the steps of: providing a housing;   providing a translation mechanism mounted upon said housing having a positioning component, said translation mechanism being actuable to move said positioning component in vertical and transverse directions between corresponding vertical end positions and transverse end positions;   providing a marker head assembly connected with said translation mechanism positioning component, having a confronting portion and an array of at least two marker pins, mutually spaced a predetermined pin-to-pin distance, each movable within a unique marking cell periphery defined by said positioning component transverse and vertical end positions, each having an impacting tip extensible from said confronting portion when actuated to form indentations in said surface at active pixel locations representing a component of said characters;   positioning said confronting portion in adjacency with said surface;   determining a locus of movement pattern for said array of marker pins representing a movement of each said marker pin to each said available pixel location of said matrix;   determining the said active pixel locations along said locus of movement pattern with respect to each said marker pin;   actuating said translation mechanism to move said positioning component in said vertical and transverse directions to cause said marker pins to move along said locus of movement pattern, the extent of movement in one said direction being uninterrupted and variable such that it is the distance required to move any said marker pin of said array in said one direction to a next encountered said active pixel; and   actuating said marker pin to form a said indentation when said marker pin is located at a said active pixel location.   
     
     
       18. The method of claim 17 in which: said locus of movement pattern is a raster pattern wherein said positioning component is moved in a predetermined transverse direction to cause said marker pins to move along one said row of said matrix and subsequently in an opposite said predetermined transverse direction and a said vertical direction to position said marker pins at a next adjacent said row of said matrix; and   said movement in one direction is along said transverse direction.   
     
     
       19. The method of claim 17 in which said step for determining the said active pixel locations along said locus of movement pattern is carried out by setting a pin mask for each said active pixel for each row of said matrix with respect to each said marker pin. 
     
     
       20. The method of claim 17 in which: said locus of movement pattern is a matrix pattern wherein said positioning component is moved in a predetermined vertical direction to cause said marker pins to move along one said column of said matrix and subsequently in a said transverse direction and a vertical direction opposite said predetermined vertical direction to move said marker pins along a next adjacent said column of said matrix; and   said movement in one direction is along said vertical direction.   
     
     
       21. The method of claim 20 in which said step for determining the said active pixel locations along said locus of movement pattern is carried out by setting a pin mask for each said actice pixel for each column of said matrix with respect to each said marker pin. 
     
     
       22. Apparatus for marking objects at a surface thereof with a sequence of pixel-based characters formed by indentation, in response to data inputs, comprising: a housing;   a translation mechanism mounted within said housing having a positioning component movable in vertical and transverse directions in response to a drive input;   a marker head assembly connectable with said positioning component, having a confronting portion positionable in adjacent with said surface and including an array of marker pins, each having an impacting tip and actuable to move into said surface in response to a pin drive input;   a translation drive assembly responsive to position signals for moving said positioning component to successive positions orienting said marker pins for forming said characters;   marker pin drive means responsive to pin actuation signals for providing said pin drive input; and   control means responsive to said data inputs for providing said drive input to position said array of marker pins for the formation of portions of said pixel-based characters at a sequence of positions while said positioning component is stationary, said control means further deriving said pin actuation signals for each said position in a sequence providing a predetermined time interval therebetween to effect a timed succession of said actuations of said marker pins avoiding the simultaneous actuation of two more said marker pins at a said position.   
     
     
       23. The apparatus of claim 22 in which said predetermined interval is about 2 milliseconds. 
     
     
       24. Marking apparatus for forming characters at the surface of an object by the select application of current from a power source to the inputs of a sequence of inductive loads in response to control inputs, comprising: a power application switch connectable between said power source and said inductive load inputs and responsive to a drive input to apply power source derived current to said inputs;   a pulse drive circuit responsive to a pulse width control input to derive said drive input;   a power selection switch network including a sequence of solid state selection switches, each having a selection output connectable in circuit completing relationship with said inductive load inputs and each having a gate input responsive to a gate input signal to transition from an initial to a gate condition to activate a corresponding said selection output thereof for effecting the said select application of current through a said inductive load;   sensing means coupled with each said power selection switch network selection output for deriving a sense signal corresponding with the comulative value of said current applied therethrough;   a gate drive network coupled with each said gate input of said solid state selection switches and responsive to said control inputs for deriving each said gate input signal;   summing means coupled with each said solid state, selection switch for deriving a summing signal having a value corresponding with the number of said solid state selection switches exhibiting a said gated condition; and   a pulse width control network responsive to said summing signal and said sense signal for deriving said pulse width control input.   
     
     
       25. The marking apparatus of claim 24 including a post actuation switch coupled with each said gate input of said solid state selection switches and responsive at the termination of a said gate input signal to effect an assured transition from said gate condition to said initial condition. 
     
     
       26. The marking apparatus of claim 24 in which said summing means comprises a network of resistors selectively coupled with each said gate input of said solid state selection switches. 
     
     
       27. The marking apparatus of claim 24 in which said pulse width control network comprises: a pulse generator for deriving a train of pulse signals; and   a comparator responsive to said summing signal as a reference input and to said sense signal for effecting a pulse width modulation of said pulse signals to effect derivation of said pulse width control input.   
     
     
       28. The method for marking a surface with indentation formed substantially continuous line characters in response to data inputs representing characters formed of data defined pixels formed within a matrix of rows and columns and in correspondence with a select pixel density of indentation pixels comprising the steps of: providing a housing;   providing a translation mechanism mounted upon said housing having a positioning component, said translation mechanism being actuable to move said positioning component in vertical and transverse directions between corresponding vertical end positions and a predetermined transverse distance between transverse end positions;   providing a marker head assembly connected with said translation mechanism positioning component, having a confronting portion and an array of at least two adjacent marker pins from first to last, mutally spaced a predetermined pin-to-pin distance, each from first to next to last being movable within a unique marking cell periphery defined by said pin-to-pin distance, each having a compacting tip extensible from said confronting portion when actuated to form indentations in said surface;   positioning said confronting portion in adjacency with said surface;   determining the number and matrix coordinate locations of said indentation pixels between adjacent said defined data pixels in correspondence with said select indentation pixel density;   actuating said translation mechanism to move to a predetermined said transverse end position;   forming at least first portions of said characters by actuating only said first marker pin at said matrix coordinate locations while actuating said translation mechanism to move said first marker pin only within said unique marking cell periphery associated therewith;   then actuating said translation mechanism to return to said predetermined transverse end position; and   then forming at least second portions of said characters by actuating only the said marker pin next to said first marker pin at said matrix coordinate locations while actuating said translation mechanism to move said next marker pin only within said unique marking cell periphery associated therewith.   
     
     
       29. The method of claim 28 including the step of expanding the transverse extent of the said unique marking cell periphery of said last marker pin by an amount corresponding with the difference between said pin-to-pin distance and said predetermined transverse distance.